Phase change materials (PCMs) are a class of material which may be used as latent heat storage media, heat transfer media and/or temperature regulating media. PCMs find many applications; for example, as heat storage media in insulating materials or building materials or as heat transfer media in heating and cooling (e.g. refrigeration) systems, or as temperature regulating media in packaging or clothing. The way in which PCMs operate is based on the enthalpy of transformation accompanying transition from the solid to the liquid phase or vice versa, which results in energy being absorbed from or released to their surroundings. They can therefore be used firstly for maintaining a constant temperature within a defined range and secondly, in a suitable arrangement, for improving heat insulation.
One application of PCMs is in the building and construction industry, offering the possibility to reduce the use of heating and air conditioning, and to maintain a comfortable temperature in light-weight buildings with low thermal mass. Other applications include the capture of low-grade process heat, storage of solar energy, and temperature regulation of heat sensitive material including living organisms such as people and animals, transplant organs and delicate electronics.
Since one phase of a PCM is a liquid phase and another phase is solid, PCMs require careful storage and containment during their use to avoid leakage. A need remains to improve one or more properties of a phase change material to improve its performance or ease of containment.